What is Phosphate Salts?

Phosphate salts refers to many different combinations of the chemical phosphate with salts and minerals. Foods high in phosphate include dairy products, whole grain cereals, nuts, and certain meats. Phosphates found in dairy products and meats seem to be more easily absorbed by the body than phosphates found in cereal grains. Cola drinks contain a lot of phosphate - so much, in fact, that they can cause too much phosphate in the blood.

People use phosphate salts for medicine. Be careful not to confuse phosphate salts with substances such as organophosphates, or with tribasic sodium phosphates and tribasic potassium phosphates, which are very poisonous.

Phosphate salts are taken by mouth for treating blood phosphate levels that are too low and blood calcium levels that are too high, and for preventing kidney stones. They are also taken for treating osteomalacia (often called "rickets" in children), a condition caused by a mineral imbalance in the body that leads to softening of the bones. Phosphate salts are also used for improving exercise performance, as an antacid for gastroesophageal reflux disease (GERD), and as a laxative for emptying the bowels before surgery.

Phosphate salts and calcium are applied to sensitive teeth to reduce pain.

Rectally, phosphate salts are used as a laxative to clean the bowels before surgery or intestinal tests.

Healthcare providers sometimes give potassium phosphate intravenously (by IV) for treating low phosphate and high calcium levels in the blood, and for preventing low phosphate in patients who are being tube-fed.

Effective for...

Preparing the bowel for a medical procedure. Sodium phosphate tablets (OsmoPrep, Visicol, Salix Pharmaceuticals, Raleigh, NC) are FDA-approved for cleansing the colon before a colonoscopy. Over-the-counter sodium phosphate solutions and enemas may also be used for bowel cleansing before medical procedures.

Low phosphate levels in the blood. Taking sodium or potassium phosphate by mouth is effective for preventing or treating low phosphate levels in the blood. Intravenous phosphate salts may also treat low phosphate levels in the blood when used under the supervision of a physician.

Likely Effective for...

Constipation. Sodium phosphate is an FDA-permitted over-the-counter (OTC) ingredient for the treatment of constipation. These products are taken by mouth or used as enemas.

Indigestion. Aluminum phosphate and calcium phosphate are FDA-permitted ingredients used in antacids.

High calcium levels in the blood. Taking phosphate salt (except calcium phosphate) by mouth is likely effective for treating high levels of calcium in the blood. But intravenous phosphate salts should not be used.

Possibly Effective for...

Possibly Ineffective for...

Athletic performance. Some early research suggests that taking sodium phosphate by mouth four times daily for 6 days might increase athletic performance in male cyclists. However, most evidence shows that taking phosphate salts by mouth does not improve exercise performance.

Insufficient Evidence to Rate Effectiveness for...

Diabetes complication (diabetic ketoacidosis). Early research suggests that taking potassium phosphate intravenously (by IV) does not improve a diabetes complication in which the body produces too many blood acids called ketones. People with this condition should only be given phosphates if they have low phosphate levels.

Complications that occur upon eating in people who were previously starving (refeeding syndrome). Limited research shows that giving sodium and potassium phosphates intravenously (by IV) over 24 hours prevents refeeding syndrome when restarting nutrition in people who are severely malnourished or starved.

How does Phosphate Salts work?

Phosphates are normally absorbed from food and are important chemicals in the body. They are involved in cell structure, energy transport and storage, vitamin function, and numerous other processes essential to health. Phosphate salts can act as laxatives by causing more fluid to be drawn into the intestines and stimulating the gut to push out its contents faster.

Are there safety concerns?

Phosphate salts containing sodium, potassium, aluminum, or calcium are LIKELY SAFE for most people when taken by mouth short-term, when sodium phosphate is inserted into the rectum appropriately and short-term, or when potassium phosphate is used intravenously (by IV) under the supervision of a physician.

Phosphate (expressed as phosphorus) is POSSIBLY UNSAFE when taken in amounts higher than 4 grams per day for adults younger than 70 years of age and 3 grams per day for people who are older.

Regular long-term use can upset the balance of phosphates and other chemicals in the body and should be monitored by a healthcare professional to avoid serious side effects. Phosphate salts can irritate the digestive tract and cause stomach upset, diarrhea, constipation, and other problems.

Do not confuse phosphate salts with substances such as organophosphates, or with tribasic sodium phosphates and tribasic potassium phosphates, which are very poisonous.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Phosphate salts from dietary sources are LIKELY SAFE for pregnant or breast-feeding women when used at the recommended allowances of 1250 mg daily for mothers between 14-18 years of age and 700 mg daily for those over 18 years of age. Other amounts are POSSIBLY UNSAFE and should only be used with the advice and ongoing care of a healthcare professional.

Children: Phosphate salts are LIKELY SAFE for children when used at the recommended daily allowances of 460 mg for children 1-3 years of age; 500 mg for children 4-8 years of age; and 1250 mg for children 9-18 years of age. Phosphate salts are POSSIBLY UNSAFE if the amount of phosphate consumed (expressed as phosphorous) exceeds the tolerable upper intake level (UL). The ULs are 3 grams per day for children 1-8 years; and 4 grams per day for children 9 years and older.

Fluid retention (edema): Avoid using phosphate salts that contain sodium if you have cirrhosis, heart failure, or other conditions that can cause edema.

High levels of calcium in the blood (hypercalcemia): Use phosphate salts cautiously if you have hypercalcemia. Too much phosphate could cause calcium to be deposited where it shouldn't be in your body.

High levels of phosphate in the blood: People with Addison's disease, severe heart and lung disease, kidney disease, thyroid problems, or liver disease are more likely than other people to develop too much phosphate in their blood when they take phosphate salts. Use phosphate salts only with the advice and ongoing care of a healthcare professional if you have one of these conditions.

Kidney disease: Use phosphate salts only with the advice and ongoing care of a healthcare professional if you have kidney problems.

Are there any interactions with medications?

BisphosphonatesInteraction Rating:
Moderate Be cautious with this combination.Talk with your health provider.

Bisphosphonate medications and phosphate salts can both lower calcium levels in the body. Taking large amounts of phosphate salts along with bisphosphonate medications might cause calcium levels to become too low.

Dosing considerations for Phosphate Salts.

The following doses have been studied in scientific research:

BY MOUTH:

For raising phosphate levels that are too low or lowering calcium levels that are too high: Healthcare providers measure the levels of phosphate and calcium in the blood and give just enough phosphate to correct the problem.

As a supplement, the recommended daily dietary allowances (RDAs) of phosphate (expressed as phosphorus) are: Children 1-3 years, 460 mg; children 4-8 years, 500 mg; men and women 9-18 years, 1250 mg; men and women over 18 years, 700 mg.

The adequate intakes (AI) for infants are: 100 mg for infants 0-6 months old and 275 mg for infants 7-12 months of age.

Tolerable Upper Intake Levels (UL), the highest intake level at which no unwanted side effects are expected, for phosphate (expressed as phosphorus) per day are: children 1-8 years, 3 grams per day; children and adults 9-70 years, 4 grams; adults older than 70 years, 3 grams; pregnant women 14-50 years, 3.5 grams; and breast-feeding women 14-50 years, 4 grams.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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